A common and well-known form of harvesting machine is a rotary combine. Rotary combines are available in various designs and models to perform the basic functions of harvesting, threshing, and cleaning of grain and other crop materials.
A typical combine includes a crop harvesting apparatus which reaps planted grain stalks and then feeds the groin stalks to a separating or threshing apparatus. The grain stalks or other crop harvested in the field is rearwardly moved from the crop harvesting apparatus and introduced for threshing to a rotor assembly by a feeder mechanism.
In an a rotary combine, the rotor assembly includes a generally tubular rotor casing mounted on the combine frame and a driven rotor disposed within the casing in coaxial relationship therewith. The rotor is supported at opposite ends by front and rear bearing assemblies. The rotor and casing have cooperating threshing instrumentalities arranged thereon for separating grain from material other than grain. In such a combine, which has been available for a number of years, the crop material is threshed several times repeatedly, but gently, as it spirals around the rotor and passes through openings in the rotor casing.
The ability to transfer crop materials from the feeder mechanism to the rotor assembly is a key factor in efficient and effective combine operations. Many rotary combines rotors include an impeller blade assembly comprised of a series of impeller blades arranged at a forward end of the rotor. During a harvesting operation, the rotating impeller blades modify the generally linear movement of the crop materials received from the feeder assembly into whirling circulatory movement in a rearward and outward direction relative to the axis of rotor rotation. As will be appreciated, those crop materials introduced from the feeder mechanism to the impeller assembly proximate to the rotary center of the impeller blades are not induced to move radially outward under the same influence as those crop materials which are introduced to the impeller assembly at a greater distance from the axis of rotation of the rotor assembly.
When rotary combines are used in certain long-stemmed leguminous or grassy crops, such as windowed perennial or annual rye grass, clover, and bent grass, there is a potential for such grassy crops to extend partially into the impeller blade assembly while the remainder of such crop materials remains partially engaged with the feeder mechanism. Such materials naturally tend to move toward the axis of rotation of the rotor assembly and some materials ultimately tend to wrap about the front rotor bearing assembly.
As will be appreciated, when the crop material becomes tightly wrapped about the rotor bearing assembly, it impairs the operational characteristics of the combine. Crop materials wrapping about the rotor bearing assembly have been known to destroy the bearing assembly and, ultimately, stall the engine of the combine. To return the combine to operation requires such crop materials to be cleaned and cleared from the bearing assembly area. To clean and clear this problem, of course, requires valuable time which is at a premium in crop harvesting operations. Moreover, when the bearing assembly is damaged, repair or replacement of the bearing assembly consumes still more valuable harvesting time. As the crop materials wrap about the forward rotor bearing assembly, the engine on the combine is required to work harder to achieve the same results. Accordingly, wrapping of crop material about the rotor bearing adversely affects combine efficiency.
Numerous designs have been proposed to maintain crop materials from becoming entangled with the front rotor bearing assembly. Most of such designs include an anti-wrap casting having any number of various configurations and which is fixedly secured to a front support member extending transversely across an open end of the rotor assembly. It has been found, however, that a scissor-like action is created between the crop materials being moved by the rotor impeller blades and such a casting. This scissor-like action of the materials against the outer surface of the casting quickly causes wear, and ultimately, requires replacement of the anti-wrap casting. As will be appreciated, the provision of a stationary casting at a forward of the rotor does not enhance or impart either outward or rearward material movement or activity at the center of the rotor during the harvesting operation.
Thus, there is a need and a desire for an anti-wrap assembly which promotes material movement at the center of the rotor so as to move the crop materials rearwardly and outwardly away from the centerline of the rotor assembly thereby promoting combine efficiency while inhibiting such materials from wrapping about the front rotor bearing assembly.